Prediction and measurement of critical properties of gasoline surrogate fuels and biofuels

Critical properties have great significance for the optimization of the combustion process of gasoline. Mixtures of n-heptane + isooctane are often used as primary reference fuels (PRF) to replace gasoline in scientific research. The critical temperatures (T_c) and critical pressures (p_c) of n-heptane + isooctane + n-propanol, n-heptane + isooctane + n-butanol and n-heptane + isooctane + ethyl propionate were measured by the flow method to study the effect of biofuels on the critical properties of traditional gasoline. The Redlich–Kister equations are used to correlate the measured data. The average absolute relative deviations for T_c and p_c are 0.10% and 0.31%, respectively. The experimental data is also used to evaluate the accuracy of the prediction model based on group contribution (GC) method previously proposed by our group.